Backlight structure and display module using the same

ABSTRACT

A backlight structure is provided. The backlight structure includes a backlight unit and a casing. The backlight unit configured to provide light to a display panel. The casing has a base portion and a support portion. The base portion surrounds the backlight unit. The support portion is connected to the base portion, and overlaps with part of the backlight unit. The support portion is for supporting the display panel thereon.

This application is a continuation application of U.S. application Ser.No. 13/175,374, filed on Jul. 1, 2011, the contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates in general to a backlight structure and a displaymodule, and more particularly to a backlight structure and a liquidcrystal display (LCD) module.

Description of the Related Art

Display modules have been used in a variety of applications, such aslap-top computers, mobile phones, or personal digital assistants. Forcurrent and next generation of mobile applications, there is a strongdemand for reducing the outline size of a display module while keeping acertain screen size thereof.

To meet this demand, the dead border is an important factor to beconsidered. Unlike the active area of a display module, the dead borderis usually an area incapable of displaying, and sometimes is referred toas a dead area. The dead border is the area from outer edges of theactive area towards the outline or outer edges of the display module.The active area and dead border together determine the outline size ofthe display module. Thus, in a case where certain active area isrequired, the dead border, or the dead area, of a display moduledetermines the outline size of itself.

Various efforts have been made for reducing the dead border. Forexample, the dead border can be reduced by making the components of andisplay module smaller, such as by narrowing the width of a metallicframe which serves as an outer frame for a display panel, by reducingthe size of a holder which supports the display panel, or by reducingthe size of a backlight unit which provides light to the display panel.

However, there are some limitations in the abovementioned means. Forexample, reducing the component size of a display module may encounterproblems in machining process, as well as in the rigidity or strength ofthe display module. In view of these limitations, it is possible thatthe components of a display module are at their allowable minimal sizesbut the dead border of the display module is still too large to meetuser's demand. Therefore, it is still an important issue for industryendeavors to reduce the dead border for a display module.

SUMMARY OF THE INVENTION

The invention is directed to a backlight structure and a display module,resulting in a narrow dead border for the display module.

According to an aspect of the present invention, a backlight structureis provided. The backlight structure includes a backlight unit and acasing. The backlight unit provides light to a display panel. The casinghas a base portion and a support portion. The base portion surrounds thebacklight unit. The support portion is connected to the base portion,and overlaps with part of the backlight unit. The support portion is forsupporting the display panel thereon.

According to another aspect of the present invention, a display moduleis provided. The display module includes a display panel, a backlightunit, and a casing. The backlight unit provides light to the displaypanel. The casing has a base portion and a support portion. The baseportion surrounds the backlight unit. The support portion is connectedto the base portion, and overlaps with part of the backlight unit. Thesupport portion is for supporting the display panel thereon.

The above and other aspects of the invention will become betterunderstood with regard to the following detailed description of thepreferred but non-limiting embodiment(s). The following description ismade with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram showing an example of a plan view of adisplay module.

FIG. 1B is a schematic diagram showing an example of a sectional view ofthe display module in FIG. 1A, wherein the sectional view is taken alonga line X-X thereof.

FIG. 2A is a schematic diagram showing an example of a plan view of adisplay module according to an embodiment of the invention.

FIG. 2B is a schematic diagram showing an example of a sectional view ofthe display module in FIG. 2A, wherein the sectional view is taken alonga line X1-X1 thereof.

FIG. 2C is an exploded diagram of a portion of the display module inFIG. 2A.

FIG. 3A is a schematic diagram showing an example of a plan view of adisplay module according to an embodiment of the invention.

FIG. 3B is a schematic diagram showing an example of a sectional view ofthe display module in FIG. 3A, wherein the sectional view is taken alonga line X2-X2 thereof.

FIG. 4A is schematic diagram showing an example of a plan view of adisplay module according to another embodiment of the invention.

FIG. 4B is a schematic diagram showing an example of a sectional view ofthe display module in FIG. 4A, wherein the sectional view is taken alonga line X3-X3 thereof.

FIG. 5A is schematic diagram showing an example of a plan view of adisplay module according to another embodiment of the invention.

FIG. 5B is a schematic diagram showing an example of a sectional view ofthe display module in FIG. 5A, wherein the sectional view is taken alonga line X4-X4 thereof.

DETAILED DESCRIPTION OF THE INVENTION

A backlight structure and a display module are provided in a number ofexemplary embodiments as follows. In an embodiment, the backlightstructure has a backlight unit whose edges are overlapped with a casingused for supporting a display panel, so that the distance from the edgesof active area to the corresponding edges of the display module can bereduced. In this way, the backlight structure and the display module canbe implemented as having a narrow dead border. Besides, the overlapbetween the casing and the edges of the backlight unit prevents opticalartifact at the edges of the backlight unit. Further description isprovided as follows with reference to accompanying drawings.

FIG. 1A is a schematic diagram showing an example of a plan view of adisplay module. In this example, the display module 10 includes adisplay panel 110, and a backlight structure 102. The display panel 110is for example a liquid crystal display panel or a touch panel. Thebacklight structure 102 includes a backlight unit 130, a casing 140 anda metal frame 150. The backlight unit 130 is for providing light to thedisplay panel 110, and is under the display panel 110, thus being shownin dashed line. The casing 140 serves as a holder for supporting thedisplay panel 110 thereon. The casing 140 can be for example made ofplastic, resin, or other material known in the art. The metal frame 150servers as a chassis for protecting the display panel 110 or othercomponent of the display module 10 from damage.

FIG. 1B is a schematic diagram showing an example of a sectional view ofthe display module in FIG. 1A, wherein the sectional view is taken alonga line X-X thereof.

The display panel 110 includes a top polarizing plate 111, an uppersubstrate 112, a display material layer 113, a lower substrate 114, aback polarizing plate 115, and a seal 116. The top polarizing plate 111and the back polarizing plate 115 are respectively disposed on the uppersubstrate 112 and the lower substrate 114, while the display materiallayer 113 is disposed between the two substrates 112 and 114. The seal116 is disposed on the surround of the two substrates 112 and 114,forming an internal space therebetween for filling display materiallayer 113 and preventing it from leakage.

The backlight unit 130 includes at least one optical film 131, a lightguide 132, and a reflector film 133. Take a number of optical films 131for example. The optical films 131 are where the light of the backlightunit 130 is emitted. The optical films 131 has a number of edges, suchas an edge E2 from the sectional view of FIG. 1B. The optical films 131include, for example, diffusing sheets and prism sheets. The light guide132 is disposed between the optical film 131 and the reflector film 133.The reflector film 133 reflects the light traveling downward from thelight guide 132 and causes it to travel toward the display panel 110.The display panel 110 is bonded to the casing 140 through a double-sideadhesive (DSA) layer 160.

There are several parameters related to the outline size of the displaymodule 10. Among them, some are illustrated with labels, such as an edgeE1 of the active area A1, an edge E2 of the optical films 131, an inneredge E3 of the casing 140, and an outer edge E4 of the metal frame 150.In addition, there are a length M between the edges E1 and E2, a gap G1between the edges E2 and E3, a gap G2 between the edges E3 and E1, and adistance D between the edges E1 and E4.

In order to reduce the outline size of the display module 10 while keepa certain screen size thereof, the dead border of the display module 10is an important factor. In FIG. 1A, the dead border is the area fromouter edges of the active area A1 of the display panel 110 towards theoutline or outer edges of the display module 10. More specifically, asshown in FIG. 1B, the dead border of the display module 10 is determinedby the distance D from the edge E1 of the active area A1 to the edge E4of the metal frame 150. As such, if the distance D can be shortened, thedisplay module 10 can have a narrower dead border.

It is found that the backlight structure of the display module 10 inFIG. 1B has limitations on shortening the distance D. Among them, onelimitation regards the distance M from the edge E1 of the active area A1to the edge E2 of the optical films 131. In the example of FIG. 1B, thedistance M is a combination of lengths M1 and M2. In addition to thelength M2 for a certain view angle denoted by dashed line VA2, thelength M1 is an additional dimension with which the edge E2 of theoptical films 131 can be prevented from being observed by users, asdenoted by dashed line VA1. Moreover, between the inner edge E3 of thecasing 140 and the edge E2 of the optical films 131, an appropriate gapG1 also is required. In view of the distance M and the gap G1, they areregarded as a requirement or limitation as to shortening the distance D,which makes it difficult to decrease the dead border.

FIG. 2A is a schematic diagram showing an example of a plan view of adisplay module according to an embodiment of the invention. In thisexample, the display module 20 differs from the display module 10 in adifferent backlight structure 202 of the display module 20. Thebacklight structure 202 has a casing 240 which is overlapped with partof the backlight unit 130. Thus, there is an overlap L between thecasing 240 and the backlight unit 130, as shown in FIG. 2A.

FIG. 2B is a schematic diagram showing an example of a sectional view ofthe display module in FIG. 2A, wherein the sectional view is taken alonga line X1-X1 thereof. More specifically, the casing 240 has a baseportion 241 and a support portion 242. The base portion 241 surroundsthe backlight unit 130. The support portion 242 is used to support thedisplay panel 110 thereon. The support portion 242 is connected to thebase portion 241. For example, the support portion 242 is extended fromthe base portion 241 towards the edge E1′ or the active area A1. In thisembodiment, the support portion 242 can be made of same materials asthat of the base portion 241, and can be made by injection molding.

The support portion 242 overlaps with part of the backlight unit 130.For example, FIG. 2C shows an exploded diagram of a portion of thedisplay module 20 is shown. As can be seen from FIG. 2C, the uppersurface of the support portion 242 is of rectangle ring shape. With thisshape, the support portion 242 can be used to cover the edges of thebacklight unit 130. Covering or overlapping means that support portion242 can be disposed over or above the backlight unit 130, and separatedfrom the backlight unit 130 by an air-gap in Z-direction Z of thicknessso that edges of the backlight unit 130 are covered by the supportportion 242.

There are several parameters related to the outline size of the displaymodule 10. Among them, some are illustrated with labels, such as an edgeE1 ′ of the active area A1, an edge E2′ of the optical films 131, aninner edge E3′ of the casing 240, and an outer edge E4′ of the metalframe 150. In addition, there are an overlap L between the edges E2′ andE3′, a gap G2′ between the edges E3′ and E1′, and a distance D′ betweenthe edges E1′ and E4′.

In this embodiment, overlapping with part of the backlight unit 130 notonly reduce the area of the dead border of the display module 20, butalso prevents the visibility of the edge E2′ of the optical films 131.As compared with the display module 10 in FIG. 1B where the backlightunit 130 prevents the visibility of the edge of the optical films 131 byusing additional length M (M=M1+M2), the display module 20 in FIG. 2Bprevents the visibility of the edge E2′ of the optical films 131 by theoverlap between the casing 240 and the backlight unit 130. As regards agap G2′ between the inner edge E3′ of the casing 240 and the edge E1′ ofthe active area A1, the display module 20 can have a smaller gap G2′comparing with the length M. Thus, the display module 20 has a smallerdistance D′ than the distance D of the display module 10. Therefore, thedisplay module 20 can be implemented as having a narrow dead border,which is defined by distance D′.

FIG. 3A is a schematic diagram showing an example of a plan view of adisplay module according to an embodiment of the invention. FIG. 3B is aschematic diagram showing an example of a sectional view of a displaymodule in FIG. 3A according to another embodiment of the invention. Thesectional view in FIG. 3B is taken along a line X2-X2 from an displaymodule 30 in FIG. 3A.

As is similar to that in FIG. 2B, the display module 30 of thisembodiment has a backlight structure 302. The backlight structure 302has a casing 340 which has a base portion 341 and a support portion 342.In addition, the support portion 342 is connected to the base portion241, and overlaps with part of the backlight unit 130, which not onlyimproves the dead border of the display module 30, but also prevents thevisibility of the edge E2′ of the optical films 131.

The display module 30 differs from the display module 20 in FIG. 2B inthat the base portion 341 and the support portion 342 can be made ofdifferent materials. In this embodiment, the support portion 342 is forexample of metal. More specifically, the support portion 342 can be ametal frame made by insert molding, and molded to a lateral side of thebase portion 341, as shown in FIG. 3B. As can be observed from thecross-section view in FIG. 3B, the metallic support portion 342 is anL-shape metal frame in this example.

The metallic support portion 342 can result in a reduced thickness ofthe display module 30. As compared with the display module 20 in FIG. 2Bwhere the support portion 242 used to support the display panel 110 ismade of injection molding materials such as resin, the metallic supportportion 342 is stronger and more rigid. Thus, the support portion 342can have a thinner thickness than that of the support portion 242.Therefore, the display module 30 can be implemented as having a reducedthickness.

FIG. 4A is a schematic diagram showing an example of a plan view of adisplay module according to another embodiment of the invention. FIG. 4Bis a schematic diagram showing an example of a sectional view of thedisplay module in FIG. 4A, wherein the sectional view is taken along aline X3-X3 thereof. As is similar to other embodiments, the displaymodule 40 has a backlight structure 402. The backlight structure 402 hasa casing 440 which has a base portion 441 and a support portion 442. Inthis example, the display module 40 differs from the display module 30in that the metal frame 150 is not included, and the display panel 110overlaps not only the base portion 441 but the metallic support portion442, as shown in FIG. 4B. In this way, the casing 440 can have anenhance strength in supporting. In this embodiment, the display module40 can also be implemented as having a narrow dead border, as well as areduced thickness.

FIG. 5A is a schematic diagram showing an example of a plan view of adisplay module according to another embodiment of the invention. FIG. 5Bis a schematic diagram showing a sectional view of the display module inFIG. 5A, wherein the sectional view is taken along a line X4-X4 thereof.As is similar to other embodiments, the display module 50 has abacklight structure 502. The backlight structure 502 has a casing 540which has a base portion 541 and a support portion 542. In this example,the display module 50 differs from the display module 40 in that themetallic support portion 542 is at the outline of the display module 50.The metallic support portion 542 is strong, rigid, and can be used forprotecting the display module 50 from damage. The support portion 542can be disposed above the base portion 541, and extended from an upperside of the base portion 541, as shown in FIG. 5B. In this embodiment,the display module 50 can also be implemented as having a narrow deadborder, as well as a reduced thickness.

According to the backlight structure and the display module disclosed inthe embodiment of the invention, the backlight unit has its edgesoverlapped with the casing used for supporting the display panel. Inthis way, the distance from the edges of active area to thecorresponding edges of the display module can be reduced. Therefore, thedisplay module can be implemented as having a reduced dead area, and thetopical artifacts caused by the edges of the optical films can beavoided. In an embodiment, in addition to a function of supporting thedisplay panel thereon, the metallic support portion can further enhancethe strength of the support portion and reduce the thickness of thedisplay module.

While the invention has been described by way of example and in terms ofthe preferred embodiment(s), it is to be understood that the inventionis not limited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

What is claimed is:
 1. A backlight structure comprising: a backlightunit for providing light to a display panel, the backlight unitcomprising an optical film; and a casing having a base portion and asupport portion, the base portion surrounding the backlight unit, thesupport portion being connected with the base portion and overlappingwith part of the backlight unit, the support portion being adapted forsupporting the display panel thereon; wherein a first gap between anedge of an active area of the display panel and an inner edge of thecasing is smaller than a second gap between an edge of the optical filmand the inner edge of the casing, wherein an upper side of the baseportion and an upper side of the support portion are below the displaypanel.
 2. The backlight structure according to claim 1, wherein theoptical film overlaps with the support portion.
 3. The backlightstructure according to claim 1, wherein an edge of the display panel isbetween an edge of the backlight unit and an edge of the supportportion.
 4. The backlight structure according to claim 1, wherein theupper surface of the support portion is of a rectangular ring shape andthe support portion overlaps the edges of the backlight unit.
 5. Thebacklight structure according to claim 1, wherein the backlight unitfurther comprises a light guide and a reflector film, and the lightguide is disposed between the optical film and the reflector film. 6.The backlight structure according to claim 1, wherein the supportportion is extended from a lateral side of the base portion.
 7. Thebacklight structure according to claim 1, wherein the support portion isextended from an upper side of the base portion.
 8. A display modulecomprising: a display panel; a backlight unit for providing light to thedisplay panel, the backlight unit comprising an optical film; and acasing having a base portion and a support portion, the base portionsurrounding the backlight unit, the support portion being connected withthe base portion and overlapping with part of the backlight unit, thesupport portion being adapted for supporting the display panel thereon;wherein a first gap between an edge of an active area of the displaypanel and an inner edge of the casing is smaller than a second gapbetween an edge of the optical film and the inner edge of the casing,wherein an upper side of the base portion and an upper side of thesupport portion are below the display panel.
 9. The display moduleaccording to claim 8, wherein the optical film overlaps with the supportportion.
 10. The display module according to claim 8, wherein an edge ofthe display panel is between an edge of the backlight unit and an edgeof the support portion.
 11. The display module according to claim 8,wherein the upper surface of the support portion is of a rectangularring shape and the support portion overlaps the edges of the backlightunit.
 12. The display module according to claim 8, wherein the backlightunit further comprises a light guide and a reflector film, and the lightguide is disposed between the optical film and the reflector film. 13.The display module according to claim 8, wherein the support portion isextended from a lateral side of the base portion.
 14. The display moduleaccording to claim 8, wherein the support portion is extended from anupper side of the base portion.
 15. The display module according toclaim 8, wherein the display panel is a liquid crystal display panel.16. The display module according to claim 8, wherein the display panelis a touch panel.